Tungsten cermet

Abstract

A tungsten cermet for use in cutting tools, including a carbonitride, having titanium and tungsten, and aluminum oxide. The cermet contains about 10 to about 50% by weight of the carbonitride, about 0.5 to about 10% by weight of aluminum oxide and tungsten as a binder. The tungsten cermet has excellent properties in toughness, impact resistance and oxidation resistance, combined with wear resistance and plastic deformation resistance, and is useful for cutting tools used in heavy cutting, hot working and the like.

What is claimed is: 
     
       1. A tungsten cermet for use in cutting tools, including a carbonitride having titanium and tungsten, the cermet consisting essentially of, about 10 to about 50% by weight of the carbonitride, about 0.5 to about 10% by weight of aluminum oxide, not more than about 1% by weight of inevitable impurities, balance tungsten. 
     
     
       2. A tungsten cermet as recited in claim 1 wherein the cermet contains about 25 to about 45% by weight of the carbonitride and about 3 to about 7% by weight of aluminum oxide. 
     
     
       3. A tungsten cermet as recited in claim 1 wherein the cermet contains about 0.25 to about 5% by weight of aluminum oxide and further contains about 0.25 to about 5% by weight of yttrium oxide. 
     
     
       4. A tungsten cermet as recited in claim 3 wherein the cermet contains about 25 to about 45% by weight of the carbonitride, about 2 to about 3.5% by weight of aluminum oxide and about 1.5 to about 3% by weight of yttrium oxide. 
     
     
       5. A blade member for cutting tools, machined from the tungsten cermet as recited in claim 1, wherein the blade member is coated with at least one layer composed of one substance selected from the group consisting of an oxide and an oxynitride of aluminum; a carbide, a nitride, a carbonitride and an oxycarbonitride of titanium; a carbide, a nitride, a carbonitride and an oxycarbonitride of zirconium; and a carbide, a nitride, a carbonitride and an oxycarbonitride of hafnium. 
     
     
       6. A blade member as recited in claim 5 wherein the thickness of the coating layer is within a range of about 0.5 to about 20 μm. 
     
     
       7. A blade member for cutting tools, machined from the tungsten cermet as recited in claim 2 wherein the blade member is coated with at least one layer composed of one substance selected from the group consisting of an oxide and an oxynitride of aluminum; a carbide, a nitride, a carbonitride and an oxycarbonitride of titanium; a carbide, a nitride, a carbonitride and an oxycarbonitride of zirconium; and a carbide, a nitride, a carbonitride and an oxycarbonitride of hafnium. 
     
     
       8. A blade member for cutting tools, machined from the tungsten cermet as recited in claim 3 wherein the blade member is coated with at least one layer composed of one substance selected from the group consisting of an oxide and an oxynitride of aluminum; a carbide, a nitride, a carbonitride and an oxycarbonitride of titanium; a carbide, a nitride, a carbonitride and an oxycarbonitride of zirconium; and a carbide, a nitride, a carbonitride and an oxycarbonitride of hafnium. 
     
     
       9. A blade member for cutting tools, machined from the tungsten cermet as recited in claim 4 wherein the blade member is coated with at least one layer composed of one substance selected from the group consisting of an oxide and an oxynitride of aluminum; a carbide, a nitride, a carbonitride and an oxycarbonitride of titanium; a carbide, a nitride, a carbonitride and an oxycarbonitride of zirconium; and a carbide, a nitride, a carbonitride and an oxycarbonitride of hafnium. 
     
     
       10. A blade member as recited in claim 7 wherein the thickness of the coating layer is within a range of about 0.5 to about 20 μm. 
     
     
       11. A blade member as recited in claim 8 wherein the thickness of the coating layer is within a range of about 0.5 to about 20 μm. 
     
     
       12. A blade member as recited in claim 9 wherein the thickness of the coating layer is within a range of about 0.5 to about 20 μm.